Solved -- can't ping

Thread view:

Enable EMail Alerts

Start New Thread

Thread rating:

gandalf@doctorTimothyMiller.com - 26 Apr 2005 19:08 GMT

Thanks to all those who tried to assist me with this issue in a
previous thread.

On two different occasions, two different people at my dialup ISP's
tech support department insisted that the ISP's server does not block
pings or traceroutes.

I made a third inquiry at the ISP, after running out of other ideas.
This time I was informed that the server blocks all ICMP traffic.

Is this really necessary? I wonder how many times my little mom and pop
ISP was the target of a ping attack, or the source of one. Probably
never!

Would blocking ICMP traffic likely interfere with proper TCP/IP
Timbuktu connections from dialup to DSL? This worked perfectly for
years. Then it stopped working about the same time that pings from my
dialup stopped working.

Thanks in advance for any replies to my new questioins.

Cheers,

Tim Miller

Reply to this Message

Heath Raftery - 29 Apr 2005 05:54 GMT

gandalf@doctortimothymiller.com wrote:

> On two different occasions, two different people at my dialup ISP's
> tech support department insisted that the ISP's server does not block
> pings or traceroutes.

> I made a third inquiry at the ISP, after running out of other ideas.
> This time I was informed that the server blocks all ICMP traffic.

Ha! Annoying isn't it? A scary trend I've seen before.

> Is this really necessary? I wonder how many times my little mom and pop
> ISP was the target of a ping attack, or the source of one. Probably
> never!

No, it's not necessary. It's stupid. Same thing happened around here -
there was that ping flood worm a while back and so the network ppl
killed pings forever. Great solution. Better solution would be to fix
the problem, but no, we'll cripple the network, and inconvenience all
the ppl doing the right things.

> Would blocking ICMP traffic likely interfere with proper TCP/IP
> Timbuktu connections from dialup to DSL? This worked perfectly for
> years. Then it stopped working about the same time that pings from my
> dialup stopped working.

Um, not sure. ICMP is typically used for diagnosis (ping and
traceroute, as you know) and that's why it gets on my nerves - blocking
all ICMP essentially leaves you in the dark without the basic,
essentially diagnostic tools. Incidentally, traceroute in Windows uses
ICMP, but traceroute in Unix (and therefore Mac OS X) uses UDP
packets.

Anyhow, ICMP is for reporting errors and status on the IP network, and
it is quite possible that Timbuktu relies on this in some way. The only
way to know for sure is to talk to the engineers behind Timbuktu, or
get your hands dirty with a network packet sniffer.

Heath

Signature

*--------------------------------------------------------*

*______________________________________m_('.')_m_________*

Reply to this Message

Mac Forum / General / Networking / April 2005

Solved -- can't ping